u-blox ANTARIS 4, Руководство по системной интеграции

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Full Power State (On State)
In Full Power State all components of the ANTARIS
®
4 chipset are powered through pin VCC . This is the standard
operation mode. Depending on CPU load, activity of the peripheral hardware and external load on the I/Os, the
actual supply current requirement may vary significantly.
Sleep State (Off State)
Within this mode the CPU is powered and the receiver can be woken up with a request on the serial
communication interface or an external interrupt.
If no computations need to be done, further power saving can be achieved by shutting down the clock.
Nevertheless, the system can still respond to interrupt sources and wake up again.
If voltage supply is always present at pin VCC , no backup battery is needed. The sleep state is useful if the
system is idle and waiting for user input or similar events. The real time clock – as it remains active and running –
can also schedule the sleep state to wake up the receiver after a pre-defined period of time.
Note When operating an Antaris
®
4 receiver over the USB Port use the Backup State rather than Sleep
State.
Backup State (Off State)
Battery Backup State is a selectable power save state in FXN mode. Contrary to Sleep State, only the RTC and the
battery backed up SRAM are powered. This results in even further reduced power consumption. The receiver is
woken-up and goes through a reset cycle when the preprogrammed off time expires or upon hardware reset.
This means, configuration changes not saved to battery backup RAM (BBR) or Flash will be lost after waking up
from the Backup State (see also section 4.8 ).
CPU Only State (Off State)
In a custom application where the ARM7 processor of the GPS receiver is needed but no GPS functionality is
required, the entire GPS part of the system can be shut down while e.g. no position output and no satellite
tracking is required and the CPU is executing the custom code. This way the customer has access to 100% of
the CPU power. (The CPU clock is still supplied from the RF section to the baseband processor.)
The RTC is still powered to allow fast startup when GPS positioning is required.
Note The Not available by default.
4.2.7.2 Position upon Request
The receiver can be configured to calculate a PVT solution upon request during the off time by:
•
The UBX - RXM (Receiver Manager) – POSREQ (Position Request) Message
•
EXTINT0 Pin
To configure the FixNOW™ Mode (FXN) use the UBX–CFG–FXN message. Use the UBX–CFG–RXM message to
enable or disable FixNOW™ Mode.
The optimal settings of the receiver depend on the requirements of the application such as required update rate
or maximum response time.
4.2.7.3 Waking up ANTARIS
®
4 GPS Receiver with external signals
If the ANTARIS
®
4 GPS Receiver has entered Sleep State and the power supply at pin VCC is present, various
triggers can wake up the receiver:
GPS Modules - System Integration Manual (SIM) (incl. Reference Design) Receiver Description
GPS.G4-MS4-05007-A1 Page 66